TESTING/LIN/clavhp.f(3)

NAME
TESTING/LIN/clavhp.f

SYNOPSIS

  Functions/Subroutines
subroutine clavhp (uplo, trans, diag, n, nrhs, a, ipiv, b, ldb, info)
CLAVHP

Function/Subroutine Documentation

  subroutine clavhp (character uplo, character trans, character diag, integer n, integer nrhs, complex, dimension( * ) a, integer, dimension( * ) ipiv, complex, dimension( ldb, * ) b, integer ldb, integer info)

CLAVHP

Purpose:

    !>
    !>    CLAVHP  performs one of the matrix-vector operations
    !>       x := A*x  or  x := A^H*x,
    !>    where x is an N element vector and  A is one of the factors
    !>    from the symmetric factorization computed by CHPTRF.
    !>    CHPTRF produces a factorization of the form
    !>         U * D * U^H     or     L * D * L^H,
    !>    where U (or L) is a product of permutation and unit upper (lower)
    !>    triangular matrices, U^H (or L^H) is the conjugate transpose of
    !>    U (or L), and D is Hermitian and block diagonal with 1 x 1 and
    !>    2 x 2 diagonal blocks.  The multipliers for the transformations
    !>    and the upper or lower triangular parts of the diagonal blocks
    !>    are stored columnwise in packed format in the linear array A.
    !>
    !>    If TRANS = 'N' or 'n', CLAVHP multiplies either by U or U * D
    !>    (or L or L * D).
    !>    If TRANS = 'C' or 'c', CLAVHP multiplies either by U^H or D * U^H
    !>    (or L^H or D * L^H ).
    !>

    !>  UPLO   - CHARACTER*1
    !>           On entry, UPLO specifies whether the triangular matrix
    !>           stored in A is upper or lower triangular.
    !>              UPLO = 'U' or 'u'   The matrix is upper triangular.
    !>              UPLO = 'L' or 'l'   The matrix is lower triangular.
    !>           Unchanged on exit.
    !>
    !>  TRANS  - CHARACTER*1
    !>           On entry, TRANS specifies the operation to be performed as
    !>           follows:
    !>              TRANS = 'N' or 'n'   x := A*x.
    !>              TRANS = 'C' or 'c'   x := A^H*x.
    !>           Unchanged on exit.
    !>
    !>  DIAG   - CHARACTER*1
    !>           On entry, DIAG specifies whether the diagonal blocks are
    !>           assumed to be unit matrices, as follows:
    !>              DIAG = 'U' or 'u'   Diagonal blocks are unit matrices.
    !>              DIAG = 'N' or 'n'   Diagonal blocks are non-unit.
    !>           Unchanged on exit.
    !>
    !>  N      - INTEGER
    !>           On entry, N specifies the order of the matrix A.
    !>           N must be at least zero.
    !>           Unchanged on exit.
    !>
    !>  NRHS   - INTEGER
    !>           On entry, NRHS specifies the number of right hand sides,
    !>           i.e., the number of vectors x to be multiplied by A.
    !>           NRHS must be at least zero.
    !>           Unchanged on exit.
    !>
    !>  A      - COMPLEX array, dimension( N*(N+1)/2 )
    !>           On entry, A contains a block diagonal matrix and the
    !>           multipliers of the transformations used to obtain it,
    !>           stored as a packed triangular matrix.
    !>           Unchanged on exit.
    !>
    !>  IPIV   - INTEGER array, dimension( N )
    !>           On entry, IPIV contains the vector of pivot indices as
    !>           determined by CSPTRF or CHPTRF.
    !>           If IPIV( K ) = K, no interchange was done.
    !>           If IPIV( K ) <> K but IPIV( K ) > 0, then row K was inter-
    !>           changed with row IPIV( K ) and a 1 x 1 pivot block was used.
    !>           If IPIV( K ) < 0 and UPLO = 'U', then row K-1 was exchanged
    !>           with row | IPIV( K ) | and a 2 x 2 pivot block was used.
    !>           If IPIV( K ) < 0 and UPLO = 'L', then row K+1 was exchanged
    !>           with row | IPIV( K ) | and a 2 x 2 pivot block was used.
    !>
    !>  B      - COMPLEX array, dimension( LDB, NRHS )
    !>           On entry, B contains NRHS vectors of length N.
    !>           On exit, B is overwritten with the product A * B.
    !>
    !>  LDB    - INTEGER
    !>           On entry, LDB contains the leading dimension of B as
    !>           declared in the calling program.  LDB must be at least
    !>           max( 1, N ).
    !>           Unchanged on exit.
    !>
    !>  INFO   - INTEGER
    !>           INFO is the error flag.
    !>           On exit, a value of 0 indicates a successful exit.
    !>           A negative value, say -K, indicates that the K-th argument
    !>           has an illegal value.
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 129 of file clavhp.f.

Author

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